Speech intelligibility and localization in a complex environment by listeners with hearing impairments

Abstract

Listeners with hearing impairments often complain of difficulties when trying to communicate in a complex environment such as a cocktail party. Explorations of the dependence of the intelligibility and localizability of speech on the number and spatial positions of simultaneous interfering sources are reported on. Target sources are sentences spoken by a female and interfering sources include other sentences or speech-shaped noise. The total number of sources played at any one time varied between one and four. Listeners with normal hearing, profound monaural deafness, and with symmetric sensorineural hearing impairments were tested. Listeners were tested without hearing aids. Previous work in free field and with virtual stimuli has shown that bilaterally hearing-impaired listeners show large intersubject differences in their performance in both speech intelligibility and localization tasks. In the present study an investigation was made to see whether these intersubject differences are related to each listener’s sensitivity to specific binaural cues. Therefore, in addition to localization and speech intelligibility, performance in discrimination of interaural time and level, as well as binaural masking level differences in each listener was measured. The goal of this study is to determine the extent to which performance on speech-based tasks can be accounted for by basic binaural abilities. [Work supported by NIH-NIDCD DC00100.]